Detection of Damage in Composite Materials by Vibrothermography

A new nondestructive inspection method, vibrothermography, has been studied here to determine its degree of application to the investigation of damage in composite materials. Subsurface damaged regions containing delaminations, relatively large matrix cracks, or matrix crazing are easily located by the method. A three-dimensional, anisotropic heat-conduction model, solved by a finite-difference method, has shown that the surface heat patterns monitored by thermography represent accurately the geometry and extent of the subsurface heat source.